Removal of non-volatile components from a catalytic cracking feed using a reject cracking catalyst



July 5, 1960 K. H. FAUL REMOVAL OF NON-VOLATILE COMPONENTS FROM ACATALYTIC CRACKING FEED USING A REJEC'I' CRACKING CATALYST REGENERA KlLNF L UTE GAS REJ EcT CATA LYs FROM 5T0 RAGE Filed Oct. 9, 1957 REJECTCATALYST TO STORAGE l 61 REACTOR FEED s'rm pme 's'rEAM REACTOR UXlLJARYAIR ATTORNEY United States Patent- 6 REMOVAL 'OF NON-VOLAIILE COMPONENTSFROM A CATALYTIC CRACKING FEED "USING A REJEC T CRACKINGCATALYSIEI'Kenneth H. Faulk, Lake CharlVe s,La., assignor to Cities York, 'N-Y a'simfiaa 8W e Filed on. 9, 1957, Sex. Na. 639,137:

3 Claim. 1,: l -8:2

Sryice Research and, Deyelppment, Company, New

This invention relates to improvements in the catalytic conversion ofhydro'carbons M6re particularly, thisfiii metals as sodium, iron;Vanadium, nickel, and 'ca fier;

poison catalyst and result inhigngfasand coke' yield 'at the expenseof'the' desired products; These undesirable ir'e's'ultsfiowin'g" fromcontaminated cracking feeds'are avoided in part in current "practice"liy"k 'eeping contaminated feed quantity are; r'niirijirnun' and byutilizing a high catalyst flushing rateto p event a biJild-up of thecontaininaiitsfin 'there'actor'bed. Quite obviouslyit'is'not'alwayspossible to avoid the use of contaminated feeds and thereforevarious" ire-treating techniques have been utilized." One method usedremeving'coke forming componentsffrom the feed is thedeasph'altingftreatm'ent"of'the' feed. "'Such'a' processWhil'e'lir'n'iting the'ca'rbon'r'esidiie which forms cokefh'as littleeffect on the metal compounds contained in thq'fee'd; Another treatmentof contaminated "feeds propos d" is" one in which the feed stock is pre-trea'tedb'y contacting the's'ame with spent catalyst prior tointroducingft'heffeed tothefluidized reaction zonefi' Typical'of thelatter is the" rocess set forth in US. 2432,64 4, Decemherlfi, 1947wherein partially spent catalyst contacts" feed containing deletefiousmate'rials"such'as'sulphurand nitrogen bases which "adversely "effectthe desired cracking" reaction. While" such a process avoids. in partth'e' u ndesirableg results flowing from the presence of contaminantsfif the feed, the utilization ofithe catalyst from thep're-treating' step in the rnainreaction zone seriously limits theeffectiveness ofthis pre -treating method; This'is particularly so whenthe hydrocarbon feed. contains the poisonous metal compounds which'ar'eprimarily responsiblefor catalyst contamination and loss of efiicie'ncy.

It is accordingly an object of) the presentlinvention to pre-treatcracking unit feed stocks in a manner that; will substantially reducecatalystfcontarninationa I It is a'further object of. thepresentinvention to reduce the amount of'non-volatile metal contaminantsnormallycatalyst are then introduced hit a se of the'same to contactzone 30:

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A further advantage over priora rt is obtained by keep! ing ine't'alcontain 'td' catalyst frfojrif us "th cracking r aches? ,"esje and otheradvantagesare obtainable accord the present -inventiori byimpraveafiempd 1 treating heav'y" earbdn and metal'containin" feedstocks, "Treatment 'freed stocks i according to thepresnt mvention witha 'portib 'f hare-565i catalyst "in e a short period. of, time"! Thebriet conta catalyst and feedva'porizes the'fe ed and: down of thecarbon for'lfiii g "icor nponei1 undesirable metal sl'dn 'the 'i'ijectfafaly' er in'icatalyst an'dyapor are sepz aira Th vapor a e r t sm ssp'me .yiw' e fl i i t conventionalfluidfcracking "read i separ lystcontaining the metal co so e-i m xm er al i W t t. he s a. a mi P s s skn her in oms? 9 5 m 1 t a O t/i 6 wa s; b ld liii m kiln 'eomainlngthe'reject, catalyst is inaj c'ie n tly high" so' that on being deliveredzone forjcdnta'ct the feed 'there 'f will meal enema-is an 1 p;

p on I the re n. n ssit svql h The P e-treating of cracking feeds ac ims dyed vapor ph se j lthods h pi results a is one msihq 0i s rr ia on hethe"presentinveiition Reiieii'in" 1 ms l i t p'z s i j a ll mami i ajecfcatalys't. This reject catalyst invent tokiln 'IQ by way ofilinel'z," Since colre' laid dpw non the reject cata introducedafilgand'is used hire as hereafter described; 1! ntr exit 13 in thefuppeifportion imdai drawal" 1in e"f6 in the bot't m utilised to removefrornjthe sy a continuous'basis, reject catalyst contain abIe'highamount of mannaulgar metals. V H 0' r -2 1w p: 4 t

'Inthe lower portion of kiln 10 a reject catalyst withdrawal line 20 is"provided. Line" 20* is connected to contact zone 30byslid'valvesiliwhichare'cohtiolled by regulator 23. Va1ves 22areu'sedto' controlthe'with dr'awal ofhot'reject catalyst'fromkiln I0a'ndtlie deliye'ry:

10m "e fimdsee ontarninating In addition to the stream of hot rejectcatalyst inttqby line 31.

duced to contactzone 30, byway of line 20 .a stream of hot contaminatedfeed aud stcam is injected to zone 30 In zone 30'the' feed and catalystare contacted for a short period of time in the dispersed state thenpassedimmediatelyito separator.;32. Separator; 32 can be of the cyclonetype or an equivalent apparatus awe-p02 The lay down of feedcontaminants on the hot reject.

I catalyst is accomplished in the contact zone 30 and is which'willeffect separation of feed vapor and hot reject catalyst are separatedwith the vaporsbeing withdrawn lines34 and 38 and passed to reactor 50directly or prcferabl y through a secondary separator 36 wherein a morecompleteseparation of vaporized feed and catalyst is accomplished andthence to reactor 50. Catalyst sepa-- r'at'edf lronyfeed cyclones 32 and36 is returned to stripping standpipe 40 by way'of lines 33 and 37.

catalyst. In separator 32the vaporized feed and reject Toelfect removalof hydrocarbon vapors from the -rejest catalysncatalyst delivered to 40is stripped with steam introduced by line 41., Hydrocarbon vapor -re-'moved 'by stripping is withdrawn from stripping standpipe 40 throughline 39 and reintroduced into the contact zone '30. or passed directlyinto line .34 or 38 by means not shown for delivery to'reactor -50.

Aftersti'ipping hydrocarbonvapors from the reject catalyst, thecontaminated particles are withdrawn from .standpi'pe 40 through sliding.control valves 42 and introduced' to line 18.. Theflowofcontaminatedreject catalyst from'standpipe 40'through-valves 42 is regulated bythe'controller 44. Qndlivery' to transfer line 18 from s'tandpipe' 40combustion supporting air introduced at 43 returns the contaminatedreject catalyst to kiln 10.

- The vaporous feed after pie-treatment in contact zone,

30and separation is passed by line 38 to reactor 50 which contains afluidized bed of catalyst, similar to the reaction bed maintained in aconventional fluidized cracking unit. Therein feed andcatalyst arecontacted under conditions which effect cracking of the feed to the de--sired products. These products'are'withdrawn through line 52 and passedto further processing equipment for further treatment according tostandard practice. Spent catalyst containing a lay down of carbon fromthe cracking reaction is continuously withdrawn from reactor 50 throughline 54 and transferred byline 56 to regenerator 60'. In regenerator 60a fluidized bed is maintained by means of which coke laid-down on thecatalyst in the cracking zone is removed by partial combustion. Afterregeneration, the hot catalyst is withdrawn from regenerator 60, throughline 62 combined with feed introduced at 63 and transferred by way ofline 64 to cracking reactor 50. The feed introduced at 63 wouldpreferably be a a light feed comparatively free of the contaminantsnormally found in the feeds introduced tothe pretreating de- V scribedabove. i

' Rej ect catalyst not suitable for further regeneration in regenerate;60 iswithdrawn by way of line 68 inter mittently or on a continuousbasisas desired and 'placed' in a storage hopper not shown. It is thiscatalystafter heating in kiln 10 which is utilized: in the pre-treatment 0f the contaminated feed contact zone- 30. Rejectcatalyst'wi'thdrawn in line-68 can be introduced directly.

to kiln 10 if desired in a continuous operation ormay be *made possibleby maintaining a temperature of at least 900 F. in the contact zone andpreferably a temperature of between about 950 and 1000 F. Contaminatedfeed] introduced at 24 Wlllb at a temperature ofjfrom about 7.00"Flo-850 and preferably will he ate temperature of about 75r0' to 800F.to facilitate the v'a'poriza-f tion of the feed and minimize cracking inthe contact zone. Steam: is injected'along with the feed to assist inyaporizing the feedby reduc'ing the partial pressure of the same sothat'a quicker and more effective contact of reject catalyst and feedcan be obtained If desired, the feed introducdin line 31 ma be .acomparatively heavy feed which has been blended with a lighter stocksuch as a virgin gas oil or cycle stock.

The vaporized feed and hot reject catalyst are per- 7 mitted to remainin thecontact zone for only every, short period of time, generally notmore than from one to three seconds so as to minimize the amount;of-crack- 'ing ofthefeeds Continuous introduction of the feed and hotreject catalyst tothe contactzone'30'will sweep previously introducedfeed and contaminated catalyst particles from the contact zoneto theprimary:cyclone'32 wherein the major separation of" catalyst andva'ponisl f accomplished. The vaporized feed, aspreviously -rnen 1tioned, is then transferred tea-secondary cyclone136 by line 34 ifdesired and thence by line '38 to regenerator 50. The feed, as. has beenindicated;'is vaporized on contact with the hot 'rejectcatalyst.However'whena comparatively light feed'is being pretreated it maybeadvantageous to'vaporize the same in a suitable heater prior tointroducing the same to the contact zone.

f In the preceding description reject catalyst has" been" generallyreferred to as,-the material upon whichcontaminants are deposited. Forpurposes of the present invention theuse of such material is preferred.However if it is desired other similar materials possessingthe necessarytemperature stability and low attrition characteristics canbe used.

. To understand more completely the effect of pre-treating acontaminated cracking feed prior to introducing the V same to a crackingunit according to the method of the- 7 present invention the followingexample is provided.

introducedintermi't tently by line 12 depending on the extent ofthecontamination build-up onthe reject cata lyst" during contact with thecontaminatedfeeds .In carrying out the treatmentof catalytic crackingfeed acciordiug. to the methodof the present invention it be necessaryto maintain the fluidized bedin kiln 10 at a tempei ature-ofapproximately 1200 F. Fluidiza-' tion of kiln 10 is obtained by theintroduction of combustion air at43. Theauxiliary air is introduced at14 at a controlled rate to keep the process in heat'balance and assistsinfluidizingthe bed in kiln 10. The quantity ofreject catalystwithdrawnin' line 16 and dumped to waste will-depend'on theamount ofreject catalyst available from 60 and on the rate-offlbuild-up ofcontaminants.

on-the catalyst. U

; reactor.

This example'is based on a treatment carried out in a unit-of the typedescribed on 10,000 b.p.d. of a 21 API. deasphalted gas oil.

Five thousandbpd. of virgin light gas oil is added to 10,000 b.p.d. ofdeasphalted gas oil. The blended stream is heated to'a temperature of750 F. andinject'ed; into contact zone together with 10,000 lbs/hr. ofsteam. Reject catalyst at a temperature of 1200" F; is withdrawn fromthe-fluidized kiln 10' at a rate of 5.8 tons/min;

and introduced intoa contact. zone'30- at a controlled rate by slidevalve 22. Contact fofthe feed and hot reject.

catalyst ismaintainedfor approximately 1% seconds after" which thecatalyst andvaporiarepassed to the primary i cyclone in. whichthecatalyst andzvapor are; separated V The vapor stream is theii-passedthrough a secon dary' cyclone and .thence to the .bed of a fluidized.cracking reactor. Approxirnatelyv Stone/day of the catalyst will remainin the vapor stream passed tojthe' cracking Catalyst removed from thefeed vapor the cycloifle is contacted in the stripping stand pipe 40with- 7,500 j lbs./hr. of steam. After contact withthe steam thestripped catalyst is withdrawn from the' stripping stand".

The density of the ntr duced nt he by arotfi e14at hs te of 00; ere rtst r te with h n t ar vided, the average catalyst residence or burningtime in kiln saar pa n ta y. lamin tes.-

To maintain a comparatively low level of contaminants on the catalystapproximately/520 tonsmay is withdrawn from the bed. This 20 tonscomprises approximately tons/day of catalyst and} tons/day off'ooke.maintain the desired inventory 20,to n's/day of reject catalyst,withdrawn" tronrtheregener r -of the cracking orr onr a storage ho peris to kiln 10;

In the table which follows an; analysis is provided ofthe dcasphalte'dgas 'oil'feed." A an, 'analysis of the"contaminant"componerits of thestream is provided prior to contact in the contact zone. In column B ananalysis of the feed after contact, with the reject catalyst isprovided:

From the foregoing table it will be quite apparent that a substantialreduction in both the non-volatile metal compounds and the carbonresidue coke of the deasphalted gas oil feed can be obtained. It will benoted that the carbon residue coke quantity is reduced by approximately90% with the metallic content of sodium, iron, nickel, and copper beingreduced by approximately 85%. The vanadium is reduced by approximately65%.

It is believed quite apparent that the reduction in contaminants in theorder suggested will have a substantial and favorable increase on theoverall eificiency of the fluid cracking unit. The removal of suchcontaminants according to the process defined prevents their delivery tothe fluid unit reactor and thus removes from the system the inherentdisadvantages resulting from their presence. Specifically, improvedyield-increased capacity, reduction in catalyst consumption, andupgrading of poor stocks can be obtained.

In a fluid cracking unit of the type shown to which 30,000 b.p.d. ofreactor feed are introduced together with the decontaminated feedintroduced by way of line 38, an increase in desirable product of from 1to 5% can be expected under normal operating conditions.

As previously pointed out, this invention avoids the deleterious efiectsof the metal containing compounds which normally deposit catalyticallyactive metals on the catalyst after regeneration. Pretreatment of thefeed according to the method described herein avoids this result at noreal increase in utility requirements, and with substantial savings incatalyst cost.

It will, of course, be understood that this invention is not limited tothe particular operating conditions or types of feed mentioned.

There is comparatively a wide choice of operating conditions which mustnecessarily be adjusted in accordance with the particularcharacteristics of the feed and the results desired. Specifically thetemperature at which the contact zone is operated may vary fromapproximately 800 F. to 1,000 F. In a similar manner both thetemperature of the catalyst Withdrawn from the kiln and the temperatureof the feed introduced into the contacting zone will be varied dependingon the temperature requirements of the contact zone. In a similar mannerthe catalyst to oil ratio will vary with both the oil temperature andthe kiln temperature and also with the contact temperature required tovaporize the oil. With respect to the operating pressures employed nearatmospheric I claim:

taining the non-volatile contaminants to a contact zone, introducingsufl'icient steam to said contact zone to reduce the partial pressure ofthe feed introduced therein, maintaining contact between the rejectcatalyst and vaporized feed for a period of time less than five seconds,passing the feed and reject catalyst to a separating zone whereinvaporized feed and reject catalyst are separated, passing the separatedfeed vapors to a secondary separating zone wherein further separation ofreject catalyst and vaporized feed is accomplished, passing theseparated vapors from the secondary separating zone to the fluidizedreaction zone of a fluid cracking unit, combining separated rejectcatalyst of the primary and secondary separating zones, subjecting thecombined catalyst streams to stripping steam, recycling stripped feedvapors to the contact zone at a point just prior to the point ofintroduction of the reject catalyst and vaporized feed to the primaryseparating zone, said stripped feed vapors being introduced to thecontact zone in a manner to aid fluidization in said zone, recycling thecombined stripped reject catalyst streams to the fluidized kiln andwithdrawing contaminated reject catalyst from the kiln to waste disposalat substantially the same rate that fresh reject catalyst is deliveredto said kiln.

2. A method of removing non-volatile components from catalytic crackingfeed stocks which comprises passing reject catalyst from a fluidizedcracking regenerator into a fluidized kiln maintained at a temperatureof at least about 1100 F., withdrawing hot reject catalyst from saidkiln and passing the same to a fluidized contact zone maintained at atemperature of at least about 900 F., introducing a hydrocarbon feedcontaining the non-volatile contaminants to a contact zone, introducingsuflicient steam to said contact zone to reduce the partial pressure ofthe feed introduced therein, maintaining contact between the rejectcatalyst and vaporized feed for a period of time less than five seconds,passing the feed and reject catalyst to a separating zone whereinvaporized feed and reject catalyst are separated, passing the separatedfeed vapors to a secondary separating zone wherein further separation ofreject catalyst and vaporized feed is accomplished, passing theseparated vapors from the secondary separating zone to the fluidizedreaction zone of a fluid cracking unit, combining separated rejectcatalyst of the primary and secondary separating zones, subjecting thecombined catalyst streams to stripping steam, recycling stripped feedvapors to the contact zone at a point just prior to the point ofintroduction of the reject catalyst and vaporized feed to the primaryseparating zone, recycling the combined stripped reject catalyst streamsto the fluidized kiln and withdrawing contarninated reject catalyst fromthe kiln to waste disposal at substantially the same rate that freshreject catalyst is delivered to said kiln.

3. A method of removing non-volatile components from catalytic crackingfeed stocks which comprises passing reject catalyst from a fluidizedcracking regenerator into a fluidized kiln maintained at a temperatureof at least about 1100 F., withdrawing hot reject catalyst from saidkiln and passing the same to a fluidized contact zone maintained at atemperature of at least s'pafatiiig z qrie,'recycling re j ec n catalystto me fluidized v 'th kin; t6 waste di spBs-ft subtgmia1iy1flieame fatethatfrsh tejct catalyst is del ivgrgd to 'said kiln.

References c 'tdiii 114;l l pfithis5mm 7 V 'UNITED' STATES PATENfIS 2378 5 2,414,973 w' 7 2,521,757

Ian. 28, 1947 S ept. 12,1 50

3. A METHOD OF REMOVING NON-VOLATILE COMPONENTS FROM CATALYTIC CRACKINGFEED STOCKS WHICH COMPRISES PASSING REJECT CATALYST FROM A FLUIDIZEDCRACKING REGENERATOR INTO A FLUIDIZED KILN MAINTAINED AT A TEMPERATUREOF AT LEAST ABOUT 1100*F., WITHDRAWING HOT REJECT CATALYST FROM SAIDKILN AND PASSING THE SAME TO A FLUIDIZED CONTACT ZONE MAINTAINED AT ATEMPERATURE OF AT LEAST ABOUT 900*F., INTRODUCING A HYDROCARBON FEEDCONTAINING THE NON-VOLATILE CONTAMINANTS TO A CONTACT ZONE, INTRODUCINGSUFFICIENT STEAM TO SAID CONTACT ZONE TO REDUCE THE PARTIAL PRESSURE OFTHE FEED INTRODUCED THEREIN, MAINTAINING CONTACT BETWEEN THE REJECTCATALYST AND VAPORIZED FEED FOR A PERIOD OF TIME LESS THAN FIVE SECONDS,PASSING THE FEED AND REJECT CATALYST ARE SEPARATING ZONE WHEREINVAPORIZED FEED AND REJECT CATALYST ARE SEPARATED, PASSING THE SEPARATEDVAPORS TO THE FLUIDIZED REACTION ZONE OF A FLUID CRACKING UNIT,SUBJECTING THE SEPARATED REJECT CATALYST TO STRIPPING GAS, RECYCLINGSTRIPPED FEED VAPORS TO THE SEPARATING ZONE, RECYCLING REJECT CATALYSTTO THE FLUIDIZED KLIN AND WITHDRAWING CONTAMINATED REJECT CATALYST FROMTHE KILN TO WASTE DISPOSAL AT SUBSTANTIALLY THE SAME RATE THAT FRESHREJECT CATALYST IS DELIVERED TO SAID KILN.